Spindle device of machine tool

ABSTRACT

A spindle device of a machine tool capable of stably injecting atomized cutting fluid from the tip of a tool device  13  when a variation in fluidity of the atomized cutting fluid occurs temporarily in atomized cutting fluid passages e 1 , e 2  or the supply of the atomized cutting fluid into the atomized cutting fluid passage e 1  is stopped and restarted, wherein the atomized cutting fluid passages e 1 , e 2  having a single passage cross section are formed in the area ranging from the spindle  1  to the tip of the tool device  13  through the atomized cutting fluid passages e 1 , e 2 , and a vacant chamber group transmission layer part  14  having a large number of vacant chambers  142  stacked thereon in multiple stages or in the state of communicating with each other and allowing the atomized cutting fluid to pass therethrough through the groups of the vacant chambers  142  is formed in the atomized cutting fluid passage e 1  or e 2.

FIELD OF THE INVENTION

The present invention relates to a spindle device of a machine tool,which ejects atomized cutting fluid from the tip of a tool device.

BACKGROUND OF THE INVENTION

In machining a machine tool, much cutting fluid is supplied to themachining point to cool and lubricate a workpiece or a tool device, orto remove cutting chips. In this case, there happen many problems suchas environmental pollution and a bad influence to human health due tocutting fluid, a big cost accompanying waste oil disposal of the cuttingfluid, a decrease in the tool device life by cooling of the workpiece,and sliding wear of the tool device due to an excess of cutting fluidduring fine cutting machining. In addition, because much cutting fluidadheres to the cutting chips during machining, the adhered cutting fluidmust be removed from the cutting chips in treating or recycling.

To settle these problems, recently, a machine tool that carries outso-called dry cutting has appeared. The dry cutting is what cuts themachining point as supplying a very small quantity of atomized cuttingfluid.

The applicant has already put in operation a machine tool that carriesout the dry cutting. Here, a spindle device of the machine tool, asshown in FIG. 11, involves a tool holder 4 fixing a tool device 13 is ona spindle 1 through a taper-shank part 5 b thereof.

In this case, a straight holder side atomized cutting fluid passage e2having a single passage cross section is provided to the tool holder 4.The passage e2 comprises a central hole “d” of a pull-stud 6, an innerhole “f” of a holder inside connecting pipe 8 and a tool device insidepassage “g” provided to the thickness of the tool device 13. Besides, aspindle side atomized cutting fluid passage e1 comprising an inner holeof an inner pipe 3 is provided to the spindle 1. Here, the inner pipe 3is provided to a rotating center of the spindle 1, having a singlepassage cross section.

While the tool device is machining, atomized cutting fluid generated byan atomized cutting fluid generator provided near the spindle 1 issupplied to the base of the passage e1. Then, the atomized cutting fluidpasses through the passage e1, thereafter spouting from the tip of thetool holder 13 through the passage e2.

In the above-mentioned conventional machine tool, the rotating speed ofthe spindle 1 varies according to the operating circumstance When therotating speed becomes large, the centrifugal force acting on theatomized cutting fluid flowing inside the passages e1 and e2 increases.Therefore, the pressure of the atomized cutting fluid near the innerperipheral surface of the passages e1 and e2 ascends; thereby promotingthe liquefaction thereof as well as inhibiting a stable supply thereof.Accordingly, there occur various bad influences such as a reduction inthe tool device life and the machining surface quality.

While the machine tool operates, the supply of the atomized cuttingfluid is frequently stopped and re-started to avoid a useless supply.When the supply is stopped, the atomized cutting fluid inside thepassages e1 and e2 escapes instantly. Accordingly, when the supply ofthe atomized cutting fluid is restarted, unless the passages e1 and e2are filled with the atomized cutting fluid, a stable supplycircumference is not accomplished and efficient operation is alsohindered.

The present invention aims to provide a spindle device of a machine toolthat can settle the above-mentioned troubles.

SUMMARY OF THE INVENTION

To achieve the above-mentioned purpose, the invention is characterizedby a spindle device of a machine tool comprising a spindle, a tooldevice installed thereon integrally, atomized cutting fluid passageseach having a single passage cross section and a vacant chamber grouptransmission layer part provided in the middle of either of the atomizedcutting fluid passages. Here, the atomized cutting fluid passages areprovided in the area ranging from the spindle to the tip of the tooldevice. Atomized cutting fluid supplied from the spindle side spoutsfrom the tip of the tool device through the atomized cutting fluidpassages. A vacant chamber group transmission layer part is formed sothat a large number of vacant chambers are stacked in multiple stages orin the state of communicating with each other, and the atomized cuttingfluid is allowed to pass therethrough.

Here, the atomized cutting fluid flowing inside the atomized cuttingfluid passages is a pressure fluid, spouting from the tip of the tooldevice through the vacant chamber group transmission layer part. In thiscase, the vacant chambers of the vacant chamber group transmission layerpart function as an atomized cutting fluid passage as well as anatomized cutting fluid accumulating space.

That is, when the atomized cutting fluid smoothly flows inside theatomized cutting fluid passages, the pressure of the atomized cuttingfluid inside the vacant chamber group transmission layer part becomeshigh in comparison with the case that it the atomized cutting fluid doesnot flow smoothly. Therefore, when the atomized cutting fluid with highpressure passes through each vacant chamber, it is accumulated therein.

On the other hand, when the atomized cutting fluid liquefies inside theatomized cutting fluid passages, it does not flow smoothly because therotating speed of the spindle becomes temporarily large. Here, thepressure of the upstream side of the vacant chamber group transmissionlayer part becomes low. Therefore, the atomized cutting fluid becomeshard to flow into the vacant chamber group transmission layer parttemporarily. In this case, the atomized cutting fluid with comparativelyhigh pressure accumulated in each vacant chamber escapes from an exitside of the vacant chamber temporarily and flows toward the downstreamside, and then acts so as to make up for the deficiency of atomizedcutting fluid.

Besides, when the supply of the atomized cutting fluid from the spindleside is stopped, the atomized cutting fluid or the liquefied cuttingfluid decreasing in pressure inside the atomized cutting fluid passagesremains in the vacant chambers of the vacant chamber group transmissionlayer part. In the first stage when the atomized cutting fluid is againsupplied from the spindle side, the cutting fluid remaining in thechambers is pushed out by propagation of the pressure wave of theatomized cutting fluid supplied to the upstream side, acting so thatshortage of cutting fluid may be compensated.

The invention is made definite as follows.

That is, the vacant chambers are composed so as to communicate with eachother through comparatively small entrances. According to this, when theatomized cutting fluid of the downstream side of the vacant chambergroup transmission layer part decreases in pressure, the atomizedcutting fluid inside the vacant chambers slowly escapes from theatomized cutting fluid entrances. Therefore the time per action ofcompensating a shortage of atomized cutting fluid leaving for the tip ofthe tool device is extended.

Besides, the vacant chamber group transmission layer part is made ofsintered metal. According to this, the vacant chamber group transmissionlayer part having a large number of vacant chambers stacked thereon inthe state of communicating with each other is formed easily and durably.

Moreover, the vacant chamber group transmission layer part is providedinside a tool holder that fixes the tool device on the spindle.According to this, complication of the inside structure of the spindleside is prevented.

Or instead of the structure just described the vacant chamber grouptransmission layer part may be provided inside the spindle. According tothis, conventional various tool devices installed on the spindle andtheir associated members can be used as they are. Therefore, productioncosts of the vacant chamber group transmission layer part become cheapin comparison with the case in which the vacant chamber grouptransmission layer part is provided to each of the various tool devicesand their associated members.

In this case, an atomized cutting fluid generator to generate theatomized cutting fluid can be provided inside the spindle, and thevacant chamber group transmission layer part can be provided between theatomized cutting fluid generator and the tool holder.

According to this, the atomized cutting fluid passages are shortened,thereby decreasing in liquefaction amount. Therefore, the atomizedcutting fluid through the vacant chamber group transmission layer partis efficiently stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a spindle device of a machine tool concerning thefirst embodiment of the invention. FIG. 1A is a sectional view from aside sight, and FIG. 1B is an enlarged sectional view showing animportant part of the spindle device.

FIG. 2 illustrates a spindle device of a machine tool concerning thesecond embodiment of the invention. FIG. 2A is a sectional view from aside sight, and FIG. 2B is a partly enlarged view.

FIG. 3 illustrates a spindle device of a machine tool concerning thethird embodiment of the invention. FIG. 3A is a sectional view from aside sight, and FIG. 3B is a partly enlarged view.

FIG. 4 illustrates a spindle device of a machine tool concerning thefourth embodiment of the invention. FIG. 4A is a sectional view from aside sight, and FIG. 4B is a partly enlarged view.

FIG. 5 illustrates a modified example of the fourth embodiment. FIG. 5Ais a sectional view from a side sight, and FIG. 5B is a partly enlargedview.

FIG. 6 illustrates another modified example of the fourth embodiment.FIG. 6A is a sectional view from a side sight, and FIG. 6B is a partlyenlarged view.

FIG. 7 illustrates a spindle device of a machine tool concerning thefifth embodiment of the invention. FIG. 7A is a sectional view from aside sight, and FIG. 7B is a partly enlarged view.

FIG. 8 illustrates a modified example of the fifth embodiment. FIG. 8Ais a sectional view from a side sight, and FIG. 8B is a partly enlargedview.

FIG. 9 illustrates another modified example of the fifth embodiment.FIG. 9A is a sectional view from a side sight, and FIG. 9B is a partlyenlarged view.

FIG. 10 is a sectional explanatory view showing a flow state of atomizedcutting fluid in a vacant chamber group transmission layer part of eachof the above-mentioned embodiments.

FIG. 11 is a sectional view from a side sight of a spindle device ofconventional examples.

PREFERRED EMBODIMENT OF THE INVENTION

The first embodiment of the invention will be explained.

In FIG. 1, 1 is a bar spindle, which is supported on a spindle supportframe 2 of a machine tool by not-illustrated bearings so as to freelyrotate around the center thereof. The spindle 1 has a central hole 1 awhose tip forms into a taper hole “a”. An inner pipe 3 is fixed at thecenter of the central hole 1 a integrally with the spindle 1.

Numeral 4 is a tool holder that is attached and detached by a toolexchange device. Here, the middle of a holder body 5 forms into a flangepart 5 a, the posterior part from the flange part 5 a into a shank part5 b, and the anterior part therefrom into a round bar-shape anterioroverhang part 5 c, respectively. Besides, the holder body 5 has an innerhole “b” at the center. A pull-stud 6 screws on the rear end of theinner hole “b”. A female screw b1 is formed on the comparatively longrange of the anterior part of the inner hole “b”, and a taper hole b2 isformed on the forefront part thereof Here, an adjusting screw 7 having amale screw on the peripheral surface is screwed into the female screwb1.

The adjusting screw 7 has an inner hole “c” whose posterior part isconnected to a central hole “d” of the pull-stud 6 through a holderinside connecting pipe 8.

A collet fastener 9 is provided to the tip of the overhang part 5 c. Thefastener 9 comprises a collet 10 that is inserted into the taper hole b2of the holder body 5, a fastening nut 11 that is screwed on the tip ofthe overhang part 5 c, and ring-shape coupling members 12 and 12 thatcombine the nut 11 with the collet 10 relatively-movably in acircumferential direction of the collet 10. A tool device 13 is insertedinto the central hole of the collet 10. The rear end of the tool device13 is inserted into the anterior part of the inner hole “c” of theadjusting screw 7, thereby supporting the tool device 13 under arearward displacement restriction. Besides, the tool device 13 body isfirmly fixed to the center of the holder body 5 by the fastener 9.

The tool holder 4 is firmly installed on the spindle 1 because thetaper-shank part 5 b is closely inserted into the taper hole “a” and thepull-stud 6 is drawn rearward by a not-illustrated clamping mechanismprovided to the central hole 1 a.

In this state, the tip of the inner pipe 3 contacts closely on the rearend surface of the pull-stud 6.

In the above-mentioned construction, an inner hole of the inner pipe 3serves as a spindle side atomized cutting fluid passage e1. Besides, thecentral hole “d” of the pull-stud 6, an inner hole “f” of the connectingpipe 8, the inner hole “c” of the adjusting screw 7 and a tool deviceinside passage “g” formed to the thickness of the tool device 13 serveas a tool holder side atomized cutting fluid passage e2.

A vacant chamber group transmission layer part 14, which ischaracteristic in this invention, is provided between the front end ofthe connecting pipe 8 and the rear end of the tool device 13 within theinner hole “c” of the adjusting screw 7 in the middle of the passage e2.As shown in FIG. 1B, the transmission layer part 14 forms a columnarmember 14 a to be closely inserted into the inner hole “c” of theadjusting screw 7. A large number of vacant chambers are stacked thereonin multiple stages or in the state of communicating with each other andthe atomized cutting fluid passes therethrough.

In this case, the columnar member 14 a is made with about 2 to 10 mm inthe diameter. Besides, each vacant chamber has a very small crosssection area in comparison with the passage e2, as well as acomparatively small entrance for atomized cutting fluid in comparisonwith the vacant chamber. Such a columnar member cuts and forms a lump ofsintered metal closely having tiny cavities.

In use of the above-mentioned spindle device, when atomized cuttingfluid is needed, a supply start instruction is given to a controlsection of the machine tool. In connection with this, the atomizedcutting fluid with pressure of about 0.3 MPa is supplied to the rear endof the passage e1 from a not-illustrated atomized cutting fluidgenerator provided near the spindle device. The atomized cutting fluidreaches the interior of the passage e2, spouting from the tip of thetool device 13 through the connecting pipe 8, the transmission layerpart 14 and the passage “g”. On the other hand, when the atomizedcutting fluid is not needed, a supply stop instruction is given to thecontrol section of the machine tool. In connection with this, the supplyof the atomized cutting fluid from the atomized cutting fluid generatorto the passage e1 is stopped.

Another embodiment is explained in order below. In this case, in theexplanation and each drawing relevant to each embodiment, the same signshall be used for the substantial same parts as the above-mentionedparts.

The second embodiment of the invention will be explained. FIG. 2 is asectional view from a side sight, which illustrates a spindle device ofa machine tool regarding this embodiment.

In the figure, bearings 15, 15 and spacers 16 a, 16 a are providedbetween the spindle 1 and the spindle support frame 2. The bearings 15,15 support the spindle 1 rotatively and the spacers 16 a, 16 a regulatethe relative position of the spindle 1, the spindle support frame 2 andthe bearings 15, 15.

Numeral 17 is a canister inserted into the anterior parallel part of thecentral hole 1 a of the spindle 1, which has one or more through holesin a radial direction on the peripheral wall. A ball member 18 is guidedinside each of the through holes movably in the radial direction of theperipheral wall. To the peripheral wall of the canister 17, isextrapolated a cylindrical clamp rod 19 guided to the central hole 1 aof the spindle 1 movably in a longitudinal direction. When the clamp rod19 moves to the front f0 to the spindle 1, the ball member 18 can moveoutside the radial direction of the spindle. Conversely, when the clamprod 18 moves backward to the spindle 1, the ball member 19 is pushed andmoved inside the radial direction of the spindle by the tip of the clamprod 19 compulsorily.

A spring receptive ring member 20 is fitly inserted into the rear endsurface of the canister 17 between the inner pipe 3 and the clamp rod19. The ring member 20 is pressed to the rear end surface of thecanister 17 by a compressed disk spring group 21 installed therebehind,keeping the position.

A pressing ring member 22, which presses the ball member 18 with theslanting surface, is fitly inserted into the anterior part between thecanister 17 and the clamp rod 19 movably in a longitudinal direction tothe clamp rod 19. A compressed spring 23 is installed between the ringmember 22 and the ring member 20. The ball member 18 is pressed insidethe radial direction of the spindle by the spring 23. This pressure actsso as to support suitably lest the tool holder 4 should come out thespindle 1 by its own weight when the clamp rod 19 moves to the front f0to the spindle 1.

An atomized cutting fluid generator 24 is provided somewhat to theinterior within the inner hole of the inner pipe 3. Cutting fluid andcompressed air are independently supplied to the generator 24 throughthe inner hole of the inner pipe 3 therebehind. The generator 24 mixesand stirs the cutting fluid and the compressed air to generate and ejectatomized cutting fluid from an opening 24 a of the front end thereof.

The anterior part from the generator 24 within the inner hole of theinner pipe 3 forms a somewhat large diameter. A cylindrical compressedair supply valve 25 is inserted near the front of the generator 24within the anterior part movably in a longitudinal direction. Besides,an extended connecting pipe member 26 is installed inside the tip of theanterior part of the inner pipe 3 through an omission preventingcylindrical member 27 movably in a longitudinal direction within thefixed limits. Moreover, a compressed spring 28 is provided between theconnecting pipe member 26 and the valve 25.

In this case, the spring 28 presses the valve 25 backward as well as theconnecting pipe member 26 to the front f0. When the pressure inside theanterior part of the inner pipe 3 goes down, the valve 25 moves to thefront and the compressed air of the generator 24 side is blown into theinner hole of the valve 25.

Here, the tool holder 4 is made with the structure that a vacant chambergroup transmission layer part 14 is removed in the above-mentionedembodiment.

In the above-mentioned construction, when installing the tool holder 4separated from the spindle 1 thereon, the taper-shank part 5 b of thetool holder 4 is pushed into the taper hole “a” of the spindle 1 underthe clamp rod 19 moving to the front f0. Therefore, the pull-stud 6pushes and displaces the ball member 18 outside the radial direction ofthe spindle, and then advances to the position shown in FIG. 2 to thecanister 17. After this advance, the clamp rod 19 is drawn and movedbackward. Therefore, the ball member 18 is pushed inside the radialdirection of the spindle, so that the tension of the clamp rod 19 iscommunicated to the pull-stud 6. Accordingly, the tool holder 4 isfirmly fixed on the spindle 1.

On the other hand, when separating the tool holder 4 fixed on thespindle 1 therefrom, the tool holder 4 is drawn to the front f0 underthe clamp rod 19 moving to the front f0. Therefore, the pull-stud 6pushes and displaces the ball member 18 outside the radial direction ofthe spindle against the spring 23, and then gets out to the front.

In the above-mentioned construction, the anterior part from thegenerator 24 within the inner hole of the inner pipe 3 serves as aspindle side atomized cutting fluid passage e1. The central hole “d” ofthe pull-stud 6, the inner hole “f” of the connecting pipe 8, the innerhole “c” of an adjusting screw 7 and the tool device inside passage “g”provided to the thickness of the tool device 13 serve as the tool holderside atomized cutting fluid cutting fluid passage e2.

The above-mentioned technical method is almost equal to what wasdisclosed on the prior application by this applicant (Japanese PatentApplication No. 196231 of 1999).

In this embodiment, the transmission layer part 14 is provided betweenthe generator 24 and the tool holder 4 within the spindle 1. Thetransmission layer part 14 is what the columnar member 14 a such as theabove-mentioned embodiment is innerly fitted and fixed to the front endpart of the inner hole of the connecting pipe member 26.

While the tool holder 4 is fixed on the spindle 1, the front end surfaceof the columnar member 14 a is pushed and moved a little backwardagainst the spring 28 by the pull-stud 6, and then closely pressed tothe rear end surface of the pull-stud 6 by the spring 28. In this case,the vacant chambers of the columnar member 14 a communicate the passagee1 of the spindle 1 side to the passage e2 of the tool holder 4 side.

On the other hand, while the tool holder 4 is drawn from the spindle 1,the columnar member 14 a is pushed to the front by the spring 28together with the connecting pipe member 26. Here, the columnar member 14 a moves to an anterior regulated position of the moving range of theconnecting pipe member 26.

In use of the above-mentioned spindle device, when the atomized cuttingfluid is needed, a supply start instruction is given to the controlsection of the machine tool. In connection with this, the compressed airand the cutting fluid are supplied from the outside of the spindledevice to the generator 24 inside the spindle 1. Therefore, thegenerator 24 supplies atomized cutting fluid with pressure of about 0.3MPa into the passage e1. The atomized cutting fluid shortly reaches theinterior of the passage e2 through the transmission layer part 14,spouting from the tip of the tool device 13 through the connecting pipe8 and the passage “g”. On the other hand, when the atomized cuttingfluid becomes useless, a supply stop instruction is given to the controlsection of the machine tool. In connection with this, the supply of thecompressed air and the cutting fluid to the generator 24 is stopped.Therefore, the generator 24 stops generating atomized cutting fluid andthe supply of the atomized cutting fluid to the passage e1 is alsostopped.

Next, the third embodiment of the invention will be explained. FIG. 3 isa sectional view, which illustrates a spindle device of a machine toolconcerning this embodiment.

As shown in the figure, a canister guide cylindrical member 29 isinnerly fitted closely to the foremost parallel part of the central hole1 a of the spindle 1. And a clamp rod 30 is inserted into an inner holeof the guide cylindrical member 29 movably in a longitudinal direction.The clamp rod 30 has a central hole 30 a. And the front of the clamp rod30 forms into a canister part 30 b. One or more through holes in theradial direction of the spindle are provided to a peripheral wall of thefront end of the canister part 30 b. A ball member 18 is inserted intoeach of the through holes movably in the radial direction of thespindle.

The compressed disk spring group 21 is inserted behind the guidecylindrical member 29 within the central hole 1 a of the spindle 1. Thespring group 21 presses the guide cylindrical member 29 to the front,and simultaneously the clamp rod 30 toward a posterior regulatedposition within the longitudinal moving range. Therefore, the guidecylindrical member 29 remains at a position shown in FIG. 3A within thespindle 1.

An extended connecting member 31 is provided to the central hole 30 abehind the canister part 30 b of the clamp rod 30. The connecting member31 is guided through an omission preventing ring member 32 screwed intothe central hole 30 a movably in a longitudinal direction within thefixed limits, and besides, pressed to the front f0 by a compressedspring 33 installed behind the ring member 32.

The tool holder 4 is made what the central hole “d” of the pull-stud 6and the tool device inside passage “g” are connected by the inner hole“b” of the holder body 5.

In the above-mentioned construction, when installing the tool holder 4separated from the spindle 1 thereon, the taper shank part 5 b of thetool holder 4 is pushed into the taper hole 1 a of the spindle 1 underthe clamp rod 30 moving to the front f0. Therefore, the pull-stud 6pushes and moves the ball member 18 outside the radial direction of thespindle, and then advances to a position shown in FIG. 3A to the guidecylindrical member 29. In this case, the clamp rod 30 moves to the frontf0 until the ball member 18 is located inside a front large-diameterpart 29 a of the inner hole of the guide cylindrical member 29. Then,the clamp rod 30 is drawn backward. Therefore, the ball member 18 ispushed inside the radial direction of the spindle by a slanting surface29 b behind the large-diameter part 29 a and fitted in a necking part ofthe clamp rod 6, and then communicates a backward tension to thepull-stud 6. Accordingly, the tool holder 4 is fixed on the spindlefirmly.

On the other hand, when separating the tool holder 4 fixed on thespindle 1 therefrom, the tool holder 4 is drawn to the front f0 underthe clamp rod 30 moving to the front f0. Therefore, the pull-stud 6pushes and moves the ball member 18 outside the radial direction of thespindle, and then gets out to the front f0.

In the above-mentioned construction, the central hole 30 a of the clamprod 30 and a part of the inner hole of the connecting pipe 31 serve as aspindle side atomized cutting fluid passage e1. Besides, the centralhole “d” of the pull-stud 6, the inner hole “b” of the holder body 5 andthe passage “g” provided to the thickness of the tool device 13 serve asa tool holder side atomized cutting fluid passage e2.

In the third embodiment as well as the second embodiment, thetransmission layer part 14 is provided inside the spindle 1. Thetransmission layer part 14 is what the columnar member 14 a such as thefirst embodiment is innerly fitted and fixed to the front end part ofthe inner hole of the connecting pipe member 31.

While the tool holder 4 is fixed on the spindle 1, the front end surfaceof the connecting pipe 31 is pushed and moved a little backward againstthe spring 33 by the pull-stud 6, and then closely pressed to the rearend surface of the pull-stud 6 by the spring 33. Here, the vacantchambers of the transmission layer part 14 connect the passage e1 to thepassage e2.

On the other hand, while the tool holder 4 is drawn from the spindle 1,the columnar member 14 a is pressed to the front f0 by the spring 33together with the connecting pipe member 31. Here, the columnar member14 a moves to the position corresponding to an anterior regulatedposition of the moving range of the connecting pipe member 31.

In use of the above-mentioned spindle device, the supply of the atomizedcutting fluid and so on is carried out in accordance with the firstembodiment.

Next, the fourth embodiment of the invention will be explained. FIG. 4is a sectional view from a side sight, which illustrates a spindledevice of a machine tool concerning this embodiment.

As shown in the figure, the front of the central hole 1 a of the spindle1 forms into a stepped hole part, and a ring-shape support member 34 isfitly inserted and bolted therein. An inner hole of the support member34 forms into a taper hole “a”. A cylindrical guide member 35 is fixedlyfitted in the central hole 1 a of the spindle 1. A draw bar 36 isinserted into an inner hole of the guide member 35 movably in alongitudinal direction.

A cylindrical clamp member 37 screws on the tip of the draw bar 36. Aspring receptacle member 38 is inserted in the central hole 1 a betweenthe clamp member 37 and the guide member 35, and besides, a cylindricalpress member 39 is inserted therein movably in a longitudinal direction.Besides, a collet 40 is installed between a peripheral surface of thepress member 39 and a peripheral wall of the central hole 1 a. Theposterior part of the inner hole of the press member 39 is made with alarge-diameter compared with the anterior part thereof. The compresseddisk spring group 21 is installed before the receptacle member 38 withinthe posterior part. Here, the spring group 21 presses the press member39 to the front f0 by spring force. Besides, a front slant surface 39 aof the press member 39 presses a rear slant surface 40 a of the collet40. The pressure of the press member 39 shrinks a diameter of theanterior part of the collet 40. In this case, 41 is a lock screw memberscrewed on a female screw formed to the central hole of the clamp member37, which fixedly joints the clamp member 37 and the draw bar 36.

The draw bar 36 has a central hole and the generator 24 is fixedlyprovided to the interior thereof. The central hole 1 a before thegenerator 24 is made with large-diameter part and the valve 25 isinstalled thereon movably in a longitudinal direction. The periphery ofthe valve 25 forms into a stepped surface. The foremost narrow-diameterpart 25 a is inserted into a central hole of the screw member 41 movablyin a longitudinal direction. Besides, a compressed spring 42 isinstalled behind the screw member 41 between an intermediate part 25 band the peripheral wall of the central hole 1 a so as to press the valve25 backward.

The tool holder 4 is a two-plane constrained HSK type having a tapershaft part 43 and a radial surface 44. An extended connecting passagemember 45 is inserted in the rear end of the inner hole “b” of theholder body 5 at a front end surface within an inner hole of the tapershaft part 43 and the tool holder 4 is fixed on the holder body 5through a cylindrical screw member 46.

In the above-mentioned construction, when installing the tool holder 4separated from the spindle 1 thereon, the taper shaft part 43 isinserted into the taper hole “a” of the spindle 1 side under the drawbar 36 and the clamp member 37 moving to the front f0, and the radialsurface 44 is closely connected with the front end surface of thesupport member 34 as shown in FIG. 4A. In this case, the tip of thethin-diameter part 25 a of the valve 25 is smoothly inserted into aninner hole of the posterior part of the connecting pipe 45 of the toolholder 4 side.

Then, the draw bar 36 is drawn and moved backward. Therefore, ananterior enormous part of the clamp member 37 pushes and moves aninterior surface of the front end of the collet 40 outside the radialdirection of the spindle and an exterior slant surface 40 b of the tipof the collet 40 is pressed to an interior slant surface of the rear endof the taper shaft part 43. This pressure generates power to draw thetaper shaft part 43 backward. The taper shaft part 43 is pressed to thetaper hole “a” of the spindle 1 side, and simultaneously the radialsurface 44 is pressed to the front end surface of the support member 34.Therefore, the tool holder 4 is firmly fixed on the spindle 1.

On the other hand, when separating the tool holder 4 fixed on thespindle 1 therefrom, the draw bar 36 and the clamp member 37 are movedto the front f0. Therefore, the collet 40 shall not bind the interiorsurface of the taper shaft part 43. Under this state, the tool holder 4is drawn to the front f0, separating from the spindle 1 side.

In the above-mentioned construction, the central hole of the valve 25serves as a spindle side atomized cutting fluid passage e1, and besides,the inner hole of the connecting member 45, the inner hole “f” of theholder inside connecting pipe 8, the inner hole “c” of the adjustingscrew 7 and the holder inside passage “g” formed the thickness of thetool device 13 serve as a tool holder side atomized cutting fluidpassage e2.

Besides, in this embodiment, the transmission layer part 14 is providedinside the tool holder 4. The transmission layer part 14 is what thecolumnar member 14 a such as shown in the first embodiment is innerlyfitted and fixed between the connecting pipe 8 and the tool device 13within the inner hole “c” of the adjusting screw 7.

In use of the above-mentioned spindle device, the supply of the atomizedcutting fluid and so on is carried out in accordance with the secondembodiment.

FIG. 5 illustrates a modification of this embodiment. In thismodification, the transmission layer part 14 is provided between thegenerator 24 and the tool holder 4 within the spindle 1. Concretely, thecolumnar member 14 a such as shown in the first embodiment is innerlyfitted and fixed inside the inner hole of the anterior thin-diameterpart 25 a of the valve 25. On the other hand, the transmission layerpart 14 inside the tool holder 4 is removed.

FIG. 6 illustrates an another modification of this embodiment. In thismodification, the generator 24 and the supply passages for supplying thecompressed air and the cutting fluid are removed. An inner pipe 47 isprovided inside the central hole of the draw bar 36 integrally. Besides,instead of the valve 25, an extended connecting pipe member 251 in thesame shape with the valve 25 is inserted inside the anteriorlarge-diameter part of the central hole of the draw bar 36 movably in alongitudinal direction. While the tool holder 4 is fixed on the spindle1, a front end surface of the inner pipe 47 is pressed on a rear endsurface of the connecting pipe member 251 by the spring 42 and an innerhole of the inner pipe 47 is connected to an inner hole of theconnecting pipe member 251.

In use of the above-mentioned spindle device, the supply of the atomizedcutting fluid and so on is carried out in accordance with the firstembodiment.

Next, the fifth embodiment of the invention will be explained. FIG. 7 isa sectional view from a side sight illustrating a spindle device of amachine tool concerning this embodiment.

In the figure, the anterior part of the central hole 1 a of the spindle1 is made a large-diameter part into which the support member 34 isfitly inserted and bolted. A cylindrical canister 48 is concentricallybolted to the backside of the support member 34. A clamp member 49 isinserted into an inner hole of the canister 48 movably in a longitudinaldirection. A hemispheric hollow 49 a and a slant surface 49 b areprovided to the periphery of the clamp member 49 in relation to thespherical member 18.

The draw bar 36 is inserted in the central hole 1 a of the spindle 1movably in a longitudinal direction and fitly connected to a rear end ofthe clamp member 49 through a cylindrical connecting member 50 and alock nut 51 screwed on the tip thereof. The compressed disk spring group21 is installed between the peripheral wall of the central hole 1 a ofthe spindle 1 and the draw bar 36 to press the draw bar 36 backward.

The atomized cutting fluid generator 24 is fixedly provided inside thecentral hole 36 a of the draw bar 36. The anterior part of the centralhole 36 a is made a large-diameter part into which the valve 25 isinserted movably in a longitudinal direction. The compressed spring 42is installed in the central hole 36 a between the valve 25 and the rearend surface of the clamp member 49 and the valve 25 is pressed backwardby elasticity. The central hole 36 a of the draw bar 36 and the innerhole of the valve 25 are connected in a straight line.

The posterior part of the inner hole “b” of the tool holder 4 of atwo-plane constrained KM type is made a large-diameter part b1 intowhich a passage member 52 connected with the posterior part of theholder inside connecting pipe 8 is inserted. Besides, a mouthpiece 53 isextrapolated to a thin-diameter part of the passage member 52 movably ina longitudinal direction. A compressed spring 54 is installed into thelarge-diameter part b1 between the mouthpiece 53 and the passage member52. Here, elasticity of the spring 54 presses the mouthpiece 53backward, and besides, fixes an engaging ring member 55 on the rear endof the large-diameter part b1 so as to regulate the mouthpiece 53 fromgetting out of the large-diameter part b1.

In the above-mentioned construction, when installing the tool holder 4separated from the spindle 1 thereon, the taper shaft part 43 of thetool holder 4 is inserted into the taper hole “a” of the spindle 1 sideunder the draw bar 36 and the clamp member 49 moving to the front f0.Here, as shown in FIG. 7A, a radial surface 44 is closely connected to afront end surface of the support member 34. In this case, the sphericalmember 18 moves inside a radial direction of the spindle so as to enterthe hemispheric hollow 49 a of the clamp member 49, and the taper shaftpart 43 of the tool holder 4 is allowed to enter the taper hole “a” ofthe spindle 1 side.

Then, the draw bar 36 is drawn and moved backward. The slant surface 49b of the clamp member 49 pushes and moves each spherical member 18outside the radial direction of the spindle 1 side, thereby pressing thespherical member 18 to a slant surface of an engaging hole 43 a of theperipheral wall of the taper shaft part 43 as shown in FIG. 7A. Thepressure generates power to draw the taper shaft part 43 backward. Thetaper shaft part 43 is pressed to the taper hole “a” of the spindle 1side, and simultaneously, the radial surface 44 is pressed to the frontend surface of the support member 34. Therefore, the tool holder 4 isfirmly fixed on the spindle 1.

On the other hand, when separating the tool holder 4 fixed on thespindle 1 therefrom, the draw bar 36 and the clamp member 37 are movedto the front f0. Therefore, each spherical member 18 moves inside theradial direction of the spindle and enters the hemispheric hollow 49 a;as a result, the taper shaft part 43 is not bound. Under this state, thetool holder 4 is drawn to the front f0, separating from the spindle 1side.

In the above-mentioned construction, the inner hole of the valve 25 andthe central hole of the clamp rod 49 serve as a spindle side atomizedcutting fluid passage e1. Besides, an inner hole of the mouthpiece 53,an inner hole of the passage member 52, the inner hole “f” of theconnecting pipe 8, the inner hole “c” of the adjusting screw 7 and theholder inside passage “g” formed to the thickness of the tool device 13serve as a tool holder side atomized cutting fluid passage e2.

Besides, in this embodiment, the transmission layer part 14 is providedinside the tool holder 4. The transmission layer part 14 is made inaccordance with the fourth embodiment.

Besides, in use of the above-mentioned spindle device, the supply of theatomized cutting fluid and so on is carried out in accordance with thesecond embodiment.

FIG. 8 illustrates a modification of this embodiment. In thismodification, the transmission layer part 14 is provided between thegenerator 24 and the tool holder 4 within the spindle 1. Concretely, thecolumnar member 14 a such as shown in the first embodiment is innerlyfitted and fixed inside the posterior part of the central hole of theclamp member 49. On the other hand, the transmission layer part 14inside the tool holder 4 is removed.

FIG. 9 illustrates an another modification of this embodiment. In thismodification, the generator 24 and the supply passages for supplying thecompressed air and the cutting fluid are removed. The inner pipe 47 isprovided inside the central hole of the draw bar 36 integrally. Besides,instead of the valve 25, the extended connecting pipe member 251 in thesame shape with the valve 25 is inserted inside the large-diameter partof the anterior part of the central hole of the draw bar 36 movably in alongitudinal direction. Here, the front end surface of the inner pipe 47is pressed on the rear end surface of the connecting pipe member 251 bythe spring 42, thereby connecting the inner hole of the inner pipe 47 tothe inner hole of the clamp member 49. In use of the above-mentionedspindle device, the supply of the atomized cutting fluid and so on iscarried out in accordance with the first embodiment.

Next, in each of the above-mentioned embodiments, fluidity that theatomized cutting fluid passes around the transmission layer part 14 willbe explained with reference to FIG. 10. Here, FIG. 10 is an explanatoryview showing the fluidity of the atomized cutting fluid in thetransmission layer part 14 of the above-mentioned each embodiment.

While the spindle 1 is rotating, the atomized cutting fluid suppliedinto the passage e1 with an adequate pressure (for example, about 0.3Mpa) reaches the transmission layer part 14 through the passage e1 ore2. The atomized cutting fluid enters the transmission layer part 14from a cutting fluid entrance surface 14 1 a thereof. Then the atomizedcutting fluid flows from each vacant chamber 142 one by one towards thedownstream side to the anterior vacant chamber 142 through an atomizedcutting fluid entrance 143 thereof. During flowing, each vacant chamber142 is filled and accumulated with the atomized cutting fluid withcomparative high pressure related to a supply pressure of the atomizedcutting fluid. Thus, when the fluidity of the atomized cutting fluidinside the transmission layer part 14 progresses, the atomized cuttingfluid reaches a cutting fluid exit surface 141 b and the cutting device13 through the passage e1 or e2 as decreasing in pressure somewhat,spouting from the tip thereof. When such the fluidity continues, theatomized cutting fluid continuously spouts from the tip of the tooldevice 13.

By the way, the rotating speed of the spindle 1 usually varies accordingto the diameter of a tool device for machining, and sometimes increasesgreatly. In this case, the atomized cutting fluid flowing inside thepassages e1 and e2 gains enough centrifugal force correspondent to therotating speed of the spindle 1. In connection with this, the atomizedcutting fluid near the peripheral wall of the passages e1 and e2increases in the pressure, thereby promoting liquefying.

When cutting fluid SL inside the atomized cutting fluid passages isincreased by the promotion of the liquefaction, an effective passagesection area of the passages e1 and e2 is decreased and the fluidity ofthe atomized cutting fluid is restricted. Therefore, the atomizedcutting fluid decreases in pressure greatly until it reaches thetransmission layer part 14.

Thus pressure dropped atomized cutting fluid is prevented from enteringfrom the entrance 141 a of the transmission layer part 14, therebydecreasing in the pressure inside the passages e1 and e2 of the exitside 141 b thereof. When such a tendency starts occurring, the atomizedcutting fluid with the comparative high pressure accumulated into eachthe vacant chamber 142 inside the transmission layer part 14 escapesunder an expansion being restricted without momentarily expanding to themaximum.

As the result, though the atomized cutting fluid which enters thetransmission layer part 14 is decreased, an amount of atomized cuttingfluid than the entering atomized cutting fluid flows into the passage e1or e2 of the exit side 141 b of the transmission layer part 14, actingso as to prevent from decreasing in pressure. Therefore, a downwardtendency of the spouting amount resulting from liquefaction that theatomized cutting fluid spouts from the tip of the tool device 13 due toa temporary rotation rise of the spindle 1 is eased.

On the other hand, the pressure of the atomized cutting fluid suppliedinto the passage e1 of the spindle 1 side becomes high temporarily, andthe supply amount is increased. However, in this case, an amount ofatomized cutting fluid is accumulated into the vacant chambers 142 groupof the transmission layer part 14, thereby temporarily preventing theincrease of escaping amount from the exit 141 b of the transmissionlayer part 14. Therefore, a temporary upward tendency of the spoutingamount that the atomized cutting fluid spouts from the tip of the tooldevice 13 is eased. Such a mitigation of the upward tendency contributesto economy of atomized cutting fluid.

Accordingly, the vacant chambers of the transmission layer part 14function as a buffer, which prevents a variation in temporary fluiditythat occurs in the downstream side of the transmission layer part 14resulting from the liquefaction inside the passage e1 or e2. Therefore,the spout of the atomized cutting fluid from the tip of the tool device13 is stabilized.

The variation in temporary fluidity in an actual machining generallyoccurs due to the rotation rise of the spindle 1 which occurs over arange of short term below 2 seconds, and the vacant chambers 142 of thetransmission layer part 14 act thereupon effectively.

Besides, during use of the machine tool, while a work is not cut or whenthe spindle is stopped rotating, the supply of the atomized cuttingfluid into the passage e1 is stopped. However, in this case, theatomized cutting fluid remained in the passage e1 tends to betemporarily prevented escaping to the downstream side of thetransmission layer part 14 by an action as the buffer. In addition, theatomized cutting fluid inside the passages e1 and e2 is accumulated inthe vacant chambers group, and the cutting fluid SL liquefied inside thepassage e1 or e2 also enters and stays in the vacant chambers 142.Therefore, the atomized cutting fluid and the liquefied cutting fluid SLare prevented escaping from the tip of the tool device 13 withoutresistance in vain.

Besides, the atomized cutting fluid accumulated into the transmissionlayer part 14 because of stopping the supply and the liquefied cuttingfluid escape toward the downstream side of the transmission layer part14, spouting from the tip of the tool device 13 in misty by the pressureof the supplied atomized cutting fluid before reaching the transmissionlayer part 14 just after beginning to be supplied into the passage e1.The spouted atomized cutting fluid makes up decrease in density of theatomized cutting fluid that spouts from the tip of the tool device 13just after beginning to be supplied, thereby stabilizing the spout.

Even if the discharge of atomized cutting fluid inside the atomizedcutting fluid passages varies temporarily by changes of the rotatingspeed of the spindle, the vacant chambers group of the vacant chambergroup transmission layer part acts as a buffer to ease the variation andlets the atomized cutting fluid spout stably. Therefore, a life of atool device is extended, machining accuracy and quality are improved,and besides, cutting fluid is economized.

Besides, during use of the machine tool, though the atomized cuttingfluid is stopped and re-started being supplied into the atomized cuttingfluid passages repeatedly, since the atomized cutting fluid of theupstream side of the vacant chamber group transmission layer part andthe liquefied cutting fluid are accumulated into the vacant chambergroup transmission layer part when the supply is stopped, they areeffectively prevented from escaping in vain. In addition, the density ofthe atomized cutting fluid spouted from the tip of the tool device justafter re-starting the supply prevents from decreasing in cutting fluiddensity excessively by the atomized cutting fluid escaping from thevacant chamber group transmission layer part and the liquefied cuttingfluid. Accordingly, a time-variation of the density of the atomizedcutting fluid spouted from the tip of the tool device is prevented.

The time to ease a temporary variation in fluidity of the atomizedcutting fluid is extended.

The vacant chamber group transmission layer part can be easily formedstrong.

The inside structure of the spindle side can be prevented fromcomplication.

Various devices installed on the spindle and associated members can gainan effect based on the vacant chamber group transmission layer part foreach tool device even if they are not alterable. Total cost to gain theeffect is cheaper in comparison with the case that the vacant chambergroup transmission layer part is provided to each of the various tooldevices and associated members.

The atomized cutting fluid passages are shortened and liquefying amountof the atomized cutting fluid is decreased, thereby effectively makingthe atomized cutting fluid spout from the tool device stably.

1. A spindle device of a machine tool comprising: a spindle; a tooldevice integrally installed on said spindle and having a tip; atomizedcutting fluid passages each having a single passage cross section formedin an area ranging from the spindle to the tip of the tool device 13;and a vacant chamber group transmission layer part formed in the middleof one of the atomized cutting fluid passages, wherein atomized cuttingfluid supplied to the vacant chamber group transmission layer part fromthe spindle side spouts from the tip of the tool device and the vacantchamber group transmission layer part has a large number of vacantchambers stacked thereon in multiple stages or in the state ofcommunicating with each other and allows the atomized cutting fluid topass through groups of the vacant chambers.
 2. A spindle device of amachine tool as claimed in claim 1, wherein the vacant chambers aremutually communicated with each other through small entrances.
 3. Aspindle device of a machine tool as claimed in claim 1, wherein thevacant chamber group transmission layer part is made of sintered metal.4. A spindle device of a machine tool as claimed in claim 1, wherein thevacant chamber group transmission layer part is provided inside a toolholder that fixes the tool device on the spindle.
 5. A spindle device ofa machine tool as claimed in claim 1, wherein the vacant chamber grouptransmission layer part is provided inside the spindle.
 6. A spindledevice of a machine tool as claimed in claim 1, wherein an atomizedcutting fluid generator is provided inside the spindle, and the vacantchamber group transmission layer part is provided between the generatorand a tool holder that fixes the tool device on the spindle.
 7. Aspindle device of a machine tool comprising: a spindle; a tool deviceinstalled on said spindle; an atomized cutting fluid passage extendingfrom the spindle to the tool device; a vacant chamber group transmissionlayer part formed in the atomized cutting fluid passage; and a flow ofatomized cutting fluid in the atomized cutting fluid passage in adirection from the spindle to the tool device, wherein the atomizedcutting fluid flows into the vacant chamber group transmission layerpart and subsequently to the tool device, and the vacant chamber grouptransmission layer part has a large number of vacant chambers arrangedin multiple stages or in the state of communicating with each other andallows the atomized cutting fluid to pass through the vacant chambers.8. A spindle device of a machine tool as claimed in claim 7, wherein thevacant chambers are mutually communicated with each other throughentrances that are smaller in area than are sections through portions ofthe vacant chambers other than the entrances.
 9. A spindle device of amachine tool as claimed in claim 7, wherein the vacant chamber grouptransmission layer part is made of sintered metal.
 10. A spindle deviceof a machine tool as claimed in claim 7, wherein the vacant chambergroup transmission layer part is provided inside a tool holder thatfixes the tool device on the spindle.
 11. A spindle device of a machinetool as claimed in claim 7, wherein the vacant chamber grouptransmission layer part is provided inside the spindle.
 12. A spindledevice of a machine tool as claimed in claim 7, wherein an atomizedcutting fluid generator is provided inside the spindle, and the vacantchamber group transmission layer part is provided between the generatorand a tool holder that fixes the tool device on the spindle.
 13. Aspindle device of a machine tool as claimed in claim 7, wherein thevacant chambers are arranged in stages that are in series with respectto the flow of atomized cutting fluid.